A typical hinge device for door and window comprises a female flap and a male flap with interfitted knuckles pivotally connected to each other by means of a hinge pin. A drawback with such a prior art hinge device is that once it is assembled and operatively installed on a door or on a window assembly, it is very easy for an intruder to dismantle such a hinge and to remove the door or window by simply pushing the hinge pin out of the knuckles. The hinge pin of such prior art hinge device also has a tendency to slightly come out of the knuckles by itself under the effect of the pivoting movement of the flaps.
Many attempts have been made in prior art to develop a security hinge that would overcome those drawbacks. However none of those prior attempts had proven to give a satisfactory solution. Hence, the security hinges developed in prior art are generally either complex and expensive to manufacture and/or inadequate, ineffective. Examples of such prior art attempts are given by example in U.S. Pat. Nos. 3,188,686; 3,621,512; 3,733,649; 3,969,788; 4,116,514; 4,135,273; 4,385,418; 4,864,692; 5,337,453; 5,666,695; and 5,711,053.
Thus, there is still a need for an adequate lockable security hinge that will be inexpensive to manufacture and thus cost-effective.